Hot-air furnace



D, A. BRUNETT.

HOT AIR FURNACE.

APPLICATION HLED FEB. 16. 1920.

1,392, 3 Patgnted 0015.4,1921.

2 SHEETSSHEET I.

D. A. BRUNETT.

HOT AIR FURNACE. APPLICATION FILED FEB. 16.. 1-920.

1 92 8 YPatentd Oct. 4, 1921;

2 SHEETSSHEET 2.

HOT-AIR FURNACE.

To all whom it may concern:

Be it known that I, Dnwrr'r A. BRUNETT, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Hot-Air Furnaces; and I do hereby declare the fol lowing to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to hot air furnaces for heating systems and has for its object to improve the same in point of efliciency, economy and control of the distribution of the heat, to wit: the hot air, to the difi'erent rooms of a building.

Generally stated, the invention consists of the novel devices and combinations of devices hereinafter described and defined in the claims. 7

The invention is illustrated in the accompanying drawings wherein like characters indicate like parts throughout the several views.

Referring to the drawings:

Figure 1 shows the improved furnace in vertical section on the line 1-1 of Fig. 2; Fig. 2 is a horizontal section on the line 22 of Fig.1;

Fig. 3 is a horizontal section on the line 33 of Fig. 1; and

Fig. 51 is a horizontal section on the irregular line 4-4 of Fig. 1.

As preferably constructed, the furnace comprises two inclosing shells 5 and 6 herein designated as the primary and secondary shells or casings, and these two shells are joined at 7, but separated by a partition 8. The tops of the two shells 5'and 6 are closed,

except for hot air delivery pipes hereinafter noted, but their. lower ends open into a common base 9. Suitably'secured within the main or primary shell 5 is a suitable fire pct 10 hav-,

ing a grate 11, and below the grate ash pit 12. A door-equipped opening 13 leads through the shell 5 into the, ash pit l2, and a door-equipped opening 14: extends through the front of the shell 5 and opens into a primary combustion chamber formed'within a metal drum or shell 15.

The drum 15 is spaced from the walls of the shell 5, its lower head is connected to thetop of the fire pot 10, and its upper Specification of Letters Patent.

Patented Oct. 4, 1921. Application filed February 16, 1920. Serial No. 358,813.

head is spaced from the upper head of said shell 5.

Av plurality of circumferentially spaced hot air tubes 16 extend through the drum or primary combustion chamber 15 and extend down to points below the ash pit 12, but terminate above the bottom of the base air chamber 9. The numeral 17 indicates a tubular air chamber that is extended downward through the upper head of the shells 5 and 15, is located axially over the fire pot 10 and has a closed head at its lower end that is located quite a distance above the top of the fire pot. A hot air tube 17 extends downward from one side of the central chamber 17 and terminates above the bottom of the base air chamber 9, much like the tube 16. .A hot air pipe 17 extends from the top of the central chamber 17 to one of the rooms of'the house or building.

Thespace above the upperhead of the inner shell or combustion chamber 15 and the upper head of the outer shell 5 is divided into a plurality of so-called air pockets 18, by radial partitions l8 that extend from the central air chamber 17 to the outer shell 5. These partitions 18 also extend down through the annular space between the shells 5 and 15, and, below the shell 15, are extended inward against the fire pot 10 and ash pit 12 and terminate, preferably, in line with the bottom of said ash pit, (notev particularly Figs. 1 and 4). There is thus formed-a pocket 18 located immediately above the upper end of each air tube 16 and a vertical passage or space 18' extends from each of these pockets between the portions 18*? downwardly around the hot air chamber and to the bottom thereof, which bottom, as shown in Fig. l, is in alinement with the bottom of the ash pit 12. The said air tubes 16, to distinguish them from other and similar tubes hereinafter described, may be treated as the primary air tubes.

Each pocket 18 is thus in communication with the upper end of one of the air tubes 16 and also is in communication with the base air chamber 9 through the outer air passages 18. Extended upward through the top of the shell 5, one from each of the pockets 18, is a hot air pipe 19. These pipes 19 will extend to different rooms, or to different parts of the same room, and to distinguish the same from similar pipes to be hereinafter described, they may be desig nated as the primary air pipes.

Located within the secondary shell or casing 6 is an inner shell or drum 20 which is spaced from the sides and top of said outer shell 6 and from the bottom of the base air chamber 9. This inner shell 20 affords what may be designated as a secondary combustion chamber or chamber for the hot gases and products of combustion; and here it should be noted that the primary combustion chamber 15 and this secondary combustion chamber 20 are connected at their intermediate portions by a short primary smoke pipe 21 (see Figs. 1 and 4). The secondary combustion chamber or shell 20 is longer than the primary combustion chamber 15 and extends down, preferably, as far as the bottom of the partition 8.

A central hot air tube 22 extends axially through the inner shell 20 and, at its upper end, is connected to a hot air pipe 23 that extends through the top of the shell 6 and to one ofthe rooms of the building. Circumferentially spaced secondary air tubes 24: also extend completely through the inner shell 20.- The space'between the tops of the shells 6 and 20 is divided into a plurality of so-called secondary air pockets 25, by means of radial partions 26 that extend from the lower portion of the air pipe 23 to the walls of the shell 6, and down to the bottom of the secondary shell 20." Here also is a pocket 25 in communication with each of the secondaryair tubes 24:, and also with the base air chamber 9 through outer air passageways 25. Secondaryhot air pipes 26 extend from the top of'the shell-6 and lead, one from each of the air pockets'25, either to different rooms or to different parts of the same room, (see'Fig. l). I An upper secondary smoke pipe 2? equipped with a damper 28 leads from the top of the inner shell or secondary combustion chamber 20 to a chimney or stack 29 and a similar, lower secondary smoke pipe 30 leads from the lower portion of said shell 20 into the smoke stack or chamber '29 and is provided with a damper 81. One, or more, usually several, cold air return pipes 32 from the room or rooms will extend to and open into the common base air chamber 9 of the hot air furnace. 7

Operation.

When the furnace is in operation, the primary combustion from the fire pot will, of course, take place in the primary combustion chamber 15, and the greatest heat will be produced therein, but the burning flames or products of combustion will pass into the secondary combustion chamber 20, and from thence, to a smoke stack or chimney. In

starting a. fire, thelower damper 31 may be closed andthe upper damper 28 will be open,

so as to get a stronger draft through the upper secondary smoke pipe 27 but after the fire has been started, the upper damper 28 will be closed and the lower damper 31 opened, so as to thereby obtain the greatest effect of the heat from the hot gases within the secondary combustion chamber. Thus, the maximum amount of heat is obtained from the combustion, and the products of the combustion are delivered to the smoke stack or chimney only in such warm condition as to insuregood draft. 1

As to the action of the air, the cold air may be drawn into thebase air chamber 9, either directly from the basement, or from the outside of the building, or through cold air return pipes from the several rooms, but in any event, will be evenly distributed to the lower ends of the several 'air tubes 16, 17 22, 24, 18 and 25, and in passing upward through said air tubes and air pockets, the air will-,of course, be heated;

Here it is important to note" that the air delivered to the two tubes that lead to any one of the primary or secondaryair pockets,

will be heated and positively delivered to that particular pocket, and from the said pocket to the particular air pipe that leads therefrom to the room or to the'particular place in the room. Otherwise stated, after. the air heating process has commenced'thereis no' chance for'recommingling of the air that is to be deliveredto' different, rooms or to different partsof the same room, and thus there is insured thep'roper proportionate delivery of air to the'several places where it is intended that itshould go in order to properly heat a house or building. 1

Aside from the advantages as to the proper delivery of air, this hot air furnace obtains a maximum amount of heat from the fuel consumed and delivers the gases or products of combustion to the chimney or stack only in such'warm condition as is'necessary to insure good draft.

What I claim is: 7 V

1. In a hot air furnace, thecombination with an outer primary casing and a secondary outer casing, said two casings having a common base air chamber, of primary and secondary drums respectively within said primary and secondary casings spaced there from at the sides, top and bottom, and aflatter, primary and secondary air pockets formed respectively over the tops of said primary and secondary combustion cham-' bers, primary and secondary hot air tubes extending respectively through said primary and secondary combustion chambers and connecting with the air chamber in the base and with the air pockets, and primary and secondary hot air pipes extending respectively from said primary and secondary air pockets.

2. In a hot air furnace, the combination with an outer primary casing and a secondary outer casing, said two casings having a common base air chamber, of primary and secondary drums, respectively, within said primary and secondary casings spaced therefrom at the sides, top and bottom and affording respectively, primary and secondary combustion chambers, a connection between the two combustion chambers for the passage of the hot gases from the former to the latter, primary and secondary air pockets formed respectively over the tops of said primary and secondary combustion chambers, primary and secondary hot air tubes extending, respectively, through said primary and secondary combustion chambers and connecting with the air chamber in the base and with the air pockets, the spaces between the sides of said primary and secondary combustion chambers and their surrounding casings being divided into outer hot air chambers that lead to the primary and secondary air pockets, and primary and secondary hot.air pipes leading, respectively,

from said primary and secondary air pockets.

3. In a hot air furnace, the combination with an outer casing having a lower air chamber and an inner drum, the latter constituting a combustion chamber, of a fire pot below and opening into said combustion chamber, an ash pit below said fire pot, the bottom of which is spaced above the bottom of the outer casing, said drum being spaced from said casing at its sides and top, means forming air pockets between the top of said drum and the top of the casing, said means extending downwardly between the sides of the drum and casing to a point in alinement with the bottom of the ash pit, a drum comprislng a closed cylinder extending downwardly into said first mentioned drum and forming a hot air chamber, a hot air pipe leading from the top of the second mentioned drum and a pipe leading from the lower portion thereof and communicating with the lower air chamber of the outer casing, air pipes leading from said air pockets and condults communicating with the inner casing forming the combustion chamber at the front and rear thereof, the conduit at the front having a hinged closure thereon and the condult at the rear forming a smoke passage.

4(- The combination with a furnace comprising a fire pot, combustion chamber and ash pit and a smoke passage leading from the combustion chamber, of a heating device comprising an outer casing having an air chamber at the base thereof. an inner chamber spaced therefrom at the top, sides and bottom with which said smoke passage communicates, means forming air pockets between the tops of the inner and outer casings, an open ended tube connecting the air chamber atthe bottom of the outer casing with a space between the tops of said casings, a hot air pipe leading from the top of said tube, open ended tubes surrounding the first mentioned tube and connecting the air chamber at the bottom of the outer casing with the air pockets formed at the top of the inner casing, hot air tubes leading from said air pockets, a smoke pipe leading from the upper portion of said inner casing adapted to lead to a chimney and having a damper therein, and a smoke pipe leading from the bottom of said inner casing adapted to lead to the chimney and having a damper therein, the damper in the upper smoke pipe being adapted to be opened only when the fire in the furnace is started and the damper in the lower smoke pipe being adapted to be opened during the normal operation of the furnace.

5. The combination with a furnace comprising a fire pot, combustion chamber and ash pit and a smoke passage leading from the combustion chamber, of a heating device comprising an outer casing having an air chamber at the base thereof, an inner chamber spaced therefrom at the top, side and bottom with which said smoke passage communicates, means forming air pockets between the tops of the inner and outer casings, a plurality of open ended tubes connecting the air chamber at the bottom of the outer casing with said air pockets formed at the top of the inner casing, hot air tubes leading from said air pockets, a smoke pipe leading from the upper portion of said inner casing adapted to lead to a chimney and having a damper therein, and a smoke pipe leading from the bottom of said inner casing adapted to lead to the chimney and having a damper therein, the damper for the upper smoke pipe being adapted to be opened only when the fire in the furnace is started and the damper in the lower smoke pipe being adapted to be opened during the normal operation of the furnace.

In testimony whereof I aflix my slgnature in presence of two witnesses.

DEVVITT A. BRUNETT. W'itnesses:

B. G. BAUMANN, HARRY D. KILeonE. 

